SMITH A O CORP — Director's Dealing 2005

May 13, 2005

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: SMITH A O CORP (AOS)
CIK: 0000091142
Period of Report: 2005-05-12

Reporting Person: MASSA RONALD E (Senior Vice President)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2005-05-12	Common Stock	M	1850	$16.667	Acquired	26456	Direct
2005-05-12	Common Stock	S	1850	$29.097	Disposed	24606	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2005-05-12	Employee Stock Options (Right to Buy)	$16.667	M	1850	Disposed	2005-10-10	Common Stock (1850)	Direct

Footnotes

F1: Options were granted under the A. O. Smith Corporation 1990 Long-Term Executive Incentive Compensation Plan, a Rule 16b-3 Plan.